Cellulose-ether solvent and composition



Tatented May 20, 1924.

STATES PATENT OFFICE.

EDWARD S. FARROW, JR., OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

CELLULOSE-ETHER SOLVENT AND COMTOSITION.

No Drawing.

To all whom it may concern:

Be it known that I, EDWARD S. FARROW, J12, a citizen of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Cellulose-Ether Solvents and Compositions, of which the following is a full, clear, and exact specification.

, This invention relates to solvents for making strong flowable solutions of cellulose ether and also relates to the cellulose ether compositions produced by the aid of such solvents. One object of my invention is to provide a solvent which will dissolve large proportions of cellulose ethers and at the same time yield solutions having a regulated viscosity for use in plastic and film making arts. Another object of my invention is to provide a cellulose ether solution, which has a regulated viscosity, for making strong, flexible, transparent film on the machines and by the methods known in the art.

In U. S. Patent No. 1,188,376, Lilienfeld, June 20, 1916, there are disclosed a series of alkyl ethers of cellulose. Certain of these are practically insoluble in water, and my invention is particularly applicable to ethers having that property, although not limited to them. Such ethers'form strong and useful solutions in mixtures of methyl acetate andv methyl alcohol. Nevertheless it is sometimes desirable to reduce the viscosity of such solutions, in order to regulate them for film manufacture, without substantially diluting them.

I have discovered that such regulation of the viscosity may be effected by adding small amounts of tribenzyl amine to the mixture of methyl acetate and methyl alcohol. Tribenzyl amine by itself does not have as much solvent action on cellulose ether as a mixture of methyl alcohol and methyl acetate. The addition of small amounts of it to such mixture would not, therefore, be expected to have a lowering effect on the viscosity of the resulting solution of cellulose ether. But an amount of tribenz l amine equal to one-seventieth of the wei t of the methyl acetate and methyl alcoho mixture,

Application filed July 7, 1922. Serial No. 573,466.

for example, will lower the viscosit of a thick solution of cellulose ether in suc mixture by about 15 to 20 per cent. This sur prising action indicatesthat the tribenzyl amine has a strong latent solvent power which ismade active under these circum stances.

The proportions may vary considerably, but I find thata solution containing 1 part by weight of tribenzyl amine to 70 parts of the mixture of methyl acetate and methyl alcohol is particularly useful, yet any dilution'of the solution is negligible. The mixture of the acetate and alcohol may vary also, but I prefer to use the ratio of 90 parts by weight of the former to 10 parts by weight of the latter.

The amount of cellulose ether dissolved in the complete viscosity-regulating solvent may, of course, beconsiderably varied. By way of example, I may dissolve 1 part of water-insoluble ethyl cellulose in from 3 to 6 partsof the mixed solvent.

It will be noted that some of the tribenzyl amine remains in the finished film formed by flowing or depositing such dopes in the usual way. Other substances which impart additional suppleness or incombustibility, or other qualities to the film may be added to the above solutions or dopes, such modifying agents being, for instance, triphenyl or tricresyl phosphate, camphor, monochlornaphthalene, etc.

The ingredients are of the ordinary commercial type sufiiciently purified for the process of film manufacture, so as to givedopes yielding films having the proper relative freedom from color.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A. composition of matter comprising cellulose ether dissolved in a mixture of methyl alcohol, methyl acetate and tribenzyl amine.

2. A flowable film-forming composition comprising an alkyl ether of cellulose dissolved in a mixture of methyl alcohol,

methyl acetate and tribenzyl amine, the

film comprising cellulose ether and tribenzyl amine.

5. As an article of manufacture a flowed, flexible, transparent film comprising Waterinsoluble ethyl cellulose and tribenzyl amine.

Signed at Rochester, New York, this 30th (lay of June, 1922.

EDWARD S. FARROW, JR. 

